Various door-operated alarm devices have been proposed heretofore, for example, those shown in the following U.S. patents: U.S. Pat. No. 834,904, Mahla; U.S. Pat. No. 3,029,425, Forrester; U.S. Pat. No. 3,261,010, Kardel; U.S. Pat. No. 2,259,696, Hulst; U.S. Pat. No. 3,175,207, Hewitt; U.S. Pat. No. 3,696,380, Murphy; and U.S. Pat. No. 3,427,608, Green.